For our MBS Xojo Images Plugin we added support for libjpeg-turbo. The new JPEGTurbo plugin part encapsulates the libraries for MacOS, Windows and Linux, all built with SIMD instructions for better performance.
In Xojo the JPEGTurboMBS module provides the API pointer, which you can pass via SetAPI functions in JPEGImporterMBS or JPEGExporterMBS classes. Then the next load or save uses the new functions which work with higher performance.
Speed improvements are notable, but of course depend on your test images and computer configurations. We have seen speed increase by factor 2 to 5 here.
Please try the classes soon and report any feedback you have. Included in 19.5pr7 upload.